The invention is directed to a safety clutch for a hand tool located in a drive train in the tool and including radially displaceable coupling members movable relative to a part in the drive chain connected to the drive motor and engageable with a power take-off spindle for transmitting rotational movement to the tool. The coupling members are displaceable by an actuating member into a position connecting the part with the power take-off spindle.
Hand tools, such as hand-held drills, screwdrivers and the like, require, for the protection of the user, a safety clutch for uncoupling the drive torque of the motor from a working tool which becomes seized in a receiving material in which the tool is working, so that the user can safely operate the hand tool.
A hand tool, as known from DE-AS 22 42 944, includes a safety clutch with balls as coupling members, with the balls being radially displaceable in a part on the drive side of the tool and being spring-loaded. When such a hand tool or drill becomes seized, the coupling members are forced out of drive recesses in the power take-off spindle, for driving a working tool such as a bit, against a spring force. As a result, the part on the drive side can rotate relative to the power take-off spindle.
In this known construction, the coupling members continue to be biased by the spring force after moving out of the recess in the power take-off spindle and remain biased against the spindle. The coupling members are supported in the part which continues to rotate mechanically and, consequently, move over the recesses of the stationary power take-off spindle in a continuous manner causing considerable residual torque which must be absorbed by the user. Such residual torque exerts high stresses on the user.